Recently, there have been concerns about limitations in the use of digital data processing equipment because of an exponential increase in the required investment in sophisticated digital equipment.
While analog data processing equipment may possess a cost advantage, there is a large volume of data conventionally stored in digital format. Therefore, a more practical solution is to use circuits capable of operating on both digital and analog data, in particular, a multiplier circuit capable of directly multiplying digital data with analog data. However, no such multiplication circuit has been taught previously.